Label applicator

ABSTRACT

A labeling device includes: a robot having articulated arms with arm sections that are articulated: together, to a robot base, and to a platform of a label pickup device. The pickup device has a base plate and a plunger. The plunger has a fixed portion mounted to the base plate and is not displaceable relative to the base plate in a longitudinal direction, has a portion that is movable in the fixed portion in the longitudinal direction toward the base plate to a retracted position, and has an end configured to pick up a label. A pressure regulator of the plunger breaks a negative pressure in the plunger. The plunger&#39;s fixed portion covers an opening of its movable portion in a gas-tight manner by of the when the movable portion in an extended position and which is not covered when in the retracted position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/520,729, filed Nov. 8, 2021, and claims benefit to European PatentApplication No. EP 20 210 355.2, filed on Nov. 27, 2020. The aboveapplications are hereby incorporated by reference herein.

FIELD

The invention relates to a labeling device, e.g., for a stretch filmpackaging machine.

BACKGROUND

EP 2 298 510 B1 describes a labeling device with a delta robot. Thedelta robot makes it possible to achieve high positioning accuracy usinginexpensive low-precision motors.

EP 2 651 769 B1 describes a labeling device having an applicator witharticulated arms, which is driven by a stepper motor. A controllercontrols the phase current of the stepper motor as a function of thecurrent speed of the applicator and the maximum rated current of thestepper motor. This makes it possible to keep the power consumption ofthe applicator low.

DE 10 2019 103 794 A1 describes a suction pad where a negative pressureis produced between a bottom wall section and a suction object byjetting out gas. A negative pressure breaking hole, which is blocked bya lid section, serves for breaking the negative pressure. A drivesection is configured to move the lid section and to thereby open orblock the negative pressure breaking hole.

Labeling devices place comparatively high demands on the control and themotors used. The motors must be self-locking in order to prevent theplatform of the labeling device from falling down and causing damage orbeing damaged in the event of a power failure. Alternatively, thelabeling device are configured such that exactly one motor is shortcircuited in the event of a power failure, whereby the platform is movedto a suitable position and damage is prevented. The platform is drivensolely by the motors, whereby the motors are comparatively heavilyloaded.

Furthermore, it has hitherto always been necessary to use an electricpressure relief valve, resulting in complexity and increased cost.Moreover, this valve generally has to be controlled separately, whichalso adds complexity. In addition, the point in time when pressurerelief is required must be determined by a sensor system.

SUMMARY

In an embodiment, the present disclosure provides a labeling device thatis used in a stretch film packaging machine. The labeling deviceincludes: a delta robot having at least two articulated arms, each ofthe articulated arms having a first arm section and a second armsection, which are articulated to one another, the articulated arms eachbeing articulated at a first end to a robot base and at a second end toa platform of a pickup device movable to pick up a label, and thearticulated arms each being pivotable about a respective axis ofrotation at the robot base and configured to be driven by a respectivemotor fixedly mounted to the robot base. The pickup device has a baseplate and a plunger for picking up the label. The plunger has a fixedportion that is mounted to the base plate and is not displaceablerelative to the base plate in a longitudinal direction of the plunger,and further has a portion that is movable in the fixed portion in thelongitudinal direction of the plunger and comprises a front endconfigured to pick up a label. The plunger includes a mechanicalpressure regulator configured to break a negative pressure in theplunger, the negative pressure being for picking up the label. Themovable portion of the plunger is displaceable in a direction of alongitudinal axis of the plunger through the fixed portion of theplunger toward the base plate to a retracted position. The movableportion of the plunger has an opening which is covered in a gas-tightmanner by the fixed portion of the plunger when the movable portion ofthe plunger is in an extended position to pick up the label and which isnot covered by the fixed portion of the plunger when the movable portionof the plunger is in the retracted position.

BRIEF DESCRIPTION OF THE DRAWINGS

Subject matter of the present disclosure will be described in evengreater detail below based on the exemplary figures. All featuresdescribed and/or illustrated herein can be used alone or combined indifferent combinations. The features and advantages of variousembodiments will become apparent by reading the following detaileddescription with reference to the attached drawings, which illustratethe following:

FIG. 1 is an isometric view of a packaging machine with a labelingdevice according to the invention;

FIG. 2 is a side view of the labeling device according to the invention;

FIG. 3 a is a first side view of a pickup device of the labeling devicewith a plunger in the extended position;

FIG. 3 b is a second side view of the pickup device with the plunger inthe extended position;

FIG. 3 c is a side view of the pickup device of the labeling device withthe plunger in the retracted position;

FIG. 4 a is a side view of the plunger in the retracted position;

FIG. 4 b is an isometric view of the plunger in the retracted position;

FIG. 4 c is a cross section through the plunger;

FIG. 4 d is a side view showing the plunger in the extended position;

FIG. 5 a is an isometric view of a tension cord of a retraction deviceof the labeling device according to the invention;

FIG. 5 b is an isometric view showing the tension cord with a powercable;

FIG. 5 c is an isometric view of a retraction device of the labelingdevice;

FIG. 6 a is an exploded view of an articulated arm of the labelingdevice; and

FIG. 6 b is a view showing the articulated arm connected to a robot baseand to the pickup device.

DETAILED DESCRIPTION

Embodiments of the present invention relate to a labeling device for astretch film packaging machine. The labeling device may have a deltarobot having at least two articulated arms, each having a first and asecond arm section, which are articulated to one another, thearticulated arms each being articulated at a first end to a robot baseand at a second end to a platform of a pickup device movable to pick upa label. The articulated arms may each be pivotable about a respectiveaxis of rotation at the robot base and driven by a respective motorfixedly mounted to the robot base.

Aspects of the present invention provide a labeling device of theabove-defined type, which is significantly simpler and more reliable inconstruction, especially with respect to the demands placed on thecontrol and the drive mechanism.

Embodiments of the present invention provide a device in a technicallyparticularly simple and surprisingly effective manner by a labelingdevice of the aforementioned type, which is characterized: in that thepickup device has a base plate and a plunger for picking up the label,in that the plunger includes a fixed portion that is mounted to the baseplate and is not displaceable relative to the base plate in thelongitudinal direction of the plunger, and further includes a portionthat is movable in the fixed portion in the longitudinal direction ofthe plunger and has a front end for picking up a label, in that theplunger has a mechanical pressure regulator for breaking a negativepressure in the plunger, which negative pressure is used to pick up thelabel, and in that the movable portion of the plunger is displaceable inthe direction of the longitudinal axis of the plunger through the fixedportion of the plunger toward the base plate to a retracted position,the movable portion of the plunger having an opening which is covered ina gas-tight manner by the fixed portion of the plunger when the movableportion of the plunger is in an extended position to pick up the labeland which is not covered by the fixed portion of the plunger when themovable portion of the plunger is in the retracted position.

The breaking of the negative air pressure occurs mechanically when themovable portion of the plunger is moved to the retracted position,without the need for electronic control or for an electronic valve. Thefixed portion of the plunger can be stably mounted to the base plate.The movable portion of the plunger contacts the fixed portion of theplunger along the longitudinal direction of the plunger, therebyallowing for particularly stable guidance of the movable portion of theplunger.

The plunger in particular extends through the base plate. When themovable portion of the plunger is in the retracted position, the frontend of the movable portion of the plunger is located closer to the baseplate then when the movable portion of the plunger is in the extendedposition. In the extended position of the plunger, the fixed portion ofthe plunger and its movable portion are in gas-tight contact with eachother. The idle state of the labeling device refers in particular to thestate in which the labeling device is turned off. In the idle state, thepickup device is in particular disposed vertically above a position inwhich the pickup device is located when it releases a label.

The pickup device is preferably moved by three articulated arms. Therespective second arm section is movable relative to the first armsection and is in particular formed of two parallel rods.

A first embodiment of the present invention, which is particularlysimple to manufacture, is characterized in that the opening is formedcloser to the rear end of the movable portion of the plunger oppositeits front end than it is to its front end. In the extended position, therear end rests against the fixed portion of the plunger, the openingbeing covered and a negative pressure being produced in the plunger topick up the label. The negative pressure causes the plunger to suck thelabel against it. In the retracted position, the rear end and theopening are spaced apart from the fixed portion of the plunger in thedirection of the longitudinal axis so that air flows through the openinginto the movable portion of the plunger and the negative pressure isrelieved to release the label from the plunger. The release of the labeloccurs when the front end of the plunger strikes a package and thepackage pushes the front end of the plunger toward the base plate. Therelief of the negative pressure in the plunger causes the label to bereleased therefrom and to be applied to the package. The release of thelabel is accomplished purely mechanically. The movable portion of theplunger is displaced from the extended position to the retractedposition in particular by a package to which the label is being applied.

In further advantageous embodiments, a suction head is mounted to thefront end of the movable portion of the plunger and connected via theplunger to a vacuum pump, which is preferably mounted to the base plate.The suction head serves to suck the label against it and thereby retainthe label on the plunger. The vacuum pump produces a negative pressurein the suction head. By mounting the vacuum pump to the base plate, theconnection between the suction head and the vacuum pump can be madeshort and thus sturdy. During application of the label to a package, thesuction head is pressed onto the package. In particular, the front endof the movable portion of the plunger is at the same time displaced bythe package toward the base plate, thereby avoiding damage to thepackage. An air hose between the plunger and the vacuum pump forwithdrawing the air is movable only with the movable portion of theplunger between the retracted position and the extended position. Theair hose is not displaceable relative to the movable portion of theplunger in the axial direction. Therefore, here is no need for a complexair path system.

A preferred embodiment of the labeling device is characterized in thatthe movable portion and/or the fixed portion of the plunger are/istubular. The plunger is in particular configured to have a cylindricalshape with a length in the direction of its longitudinal axis greaterthan its width. The movable portion of the plunger is in particularguided in the fixed portion of the plunger, preferably in a telescopicmanner. The fixed portion of the plunger contacts the movable portionalong the circumference of the movable portion. The movable portion ofthe plunger is guided in the fixed portion in a particularly stablemanner.

In another preferred embodiment, when the movable portion of the plungeris in the unloaded condition, it is retained in the extended position bya spring element. The movable portion of the plunger is transferred fromthe extended position to the retracted position against the spring forceand is retained in the extended position in a stable manner without theaction of external forces, or is elastically returned from the retractedposition to the extended position. During application of a label to apackage, the front end of the movable portion of the plunger isdisplaced by the package toward the base plate against the spring forceso that the package is not damaged. The spring element is disposed inparticular between the movable portion of the plunger and the fixedportion of the plunger or the base plate.

In another advantageous embodiment, the labeling device is characterizedin that the movable portion and/or the fixed portion of the plungerare/is mounted so as to be rotatable relative to the base plate aboutthe longitudinal axis of the plunger, and preferably movable by a rotarymotor. The movable portion and/or the fixed portion of the plungerare/is disposed in particular in a rotary bearing in the base plate. Ina preferred variant, the fixed portion is immovably secured to the baseplate, and the movable portion is rotatably supported in the fixedportion. The rotatable support of the plunger serves to allow the labelsucked onto the front end of the movable portion of the plunger to bealigned during application of the label to a package. For embodimentswhere the rotary motor for rotating the plunger is disposed on the baseplate, a comparatively simple gear mechanism is sufficient to rotate theplunger.

One class of advantageous embodiments is characterized in that apermanent magnet is mounted to the rear end of the movable portion ofthe plunger opposite the front end of the movable portion of theplunger, the pickup device having a Hall-effect sensor for measuring themagnetic field of the permanent magnet, and the Hall-effect sensor beingconnected to a control unit for detecting displacement of the movableportion of the plunger. The Hall-effect sensor is used to measure themovement of the permanent magnet via the change in the magnetic fieldcaused by such movement. Consequently, the movement of the rear end ofthe movable portion of the plunger is measured since the permanentmagnet is mounted to the rear end. Thus, it is possible to measurewhether the movable portion has moved relative to a package. This isbecause the package pushes the movable portion in the direction oppositeto the movement of the articulated arm during application of the labels,so that the movable portion of the plunger is displaced relative to thefixed portion of the plunger in the direction opposite to the movementof the pickup device or pickup unit during application of the label tothe package. The control then stops in particular a movement of thearticulated arm toward the package during application of a label ortoward the label during pickup of the same from a label printer,preferably in a downward direction. Subsequently, the control moves thearticulated arm in the opposite direction to carry the label to thepackage or to pick up a new label.

In a refinement of the aforementioned embodiments, the Hall-effectsensor and the permanent magnet are located at the same height relativeto the base plate when the movable portion of the plunger is in theextended position. Due to the spatial proximity of the permanent magnetand the Hall-effect sensor, the magnetic field generated by thepermanent magnet is comparatively strong at the location of theHall-effect sensor and is readily detectable. When the Hall-effectsensor detects from a change in the magnetic field that the magnet is nolonger at the level of the Hall-effect sensor, then the Hall-effectsensor provides a signal to the control unit indicating that the plungerhas struck a package. The control then provides the signal to thearticulated arm to perform a movement away from the package.

In another class of preferred embodiments, the robot base is connectedto the platform by a return element for mechanically returning thepickup device against gravity to its home position in the idle state ofthe robot. The return element assists the motors in moving thearticulated arms back upward to remove the respective articulated armfrom the package after the label has been applied to the package. Thisreduces the load on the motors during movement of the articulated armsagainst gravity.

Refinements of these embodiments are characterized in that the returnelement has an elastic tension cord, in particular of rubber or latex.The elastic cord is tensioned when the articulated arms are moved toapply the labels. Such movement takes place in particular downwardly inthe direction of gravity, utilizing the pickup device's own weight. Thereturn movement takes place under relaxation of the previously tensionedelastic cord, in particular against gravity, so that the spring force ofthe tensioned elastic cord assist in the work of the motors. If in theevent of a short circuit, the pickup device falls freely, in particularonto a heat-sealing plate for bonding a packaging film of the package,the elastic tension cord counteracts the free fall, so that damage isavoided.

Thus, the return element serves a protective function for the pickupdevice.

A particularly advantageous embodiment of the aforementioned refinementsis characterized in that a power cable for supplying power to the pickupdevice is arranged on and carried by the tension cord. The power cableis in particular wound thereon. It has in particular the shape of atelephone cord. Thus, the length of the power cable is variablychangeable in the direction of the longitudinal axis of the tensioncord.

Another class of embodiments of the labeling device is characterized inthat each of the second arm sections of the articulated arms has a firstand/or a second end with a lug having an in particular circular,outwardly slotted through-receptacle for holding a spherical screw head.The second arm section in particular connects the first arm section tothe pickup device. The through-hole of the lug is formed by an innerradius of the lug, which inner radius does not have a cylindrical, but areciprocal spherical geometry. When a spherical screw head or a screwhead is inserted into the lug, the lug is in particular forced apart.Upon insertion, the lug clamps the spherical screw head therein so thatit cannot slide out sideways. In particular, the legs of the lug form aretainer on both sides of the slotted through-receptacle, the legs beingcapable of being forced apart relatively easily. The respective screw isfixed in particular in the pickup device and/or the first arm section.The second arm sections are non-destructively detachable from the firstarm section and/or the pickup device, especially in the event of amalfunction of the labeling device.

Refinements of this class of embodiments are characterized in thatspherical screw heads are inserted in the lugs at the ends of the firstand/or second arm sections to connect the arm sections to one anotherand/or to the platform and/or to the robot base, the lugs embracing thespherical screw heads frictionally, and possibly also with a form fit.The platform and the robot base are rotatable relative to the firstand/or second arm sections in three-dimensional space. This allows forbetter alignment of the platform and the robot base. In addition, thisenables manufacture with slightly looser tolerances.

Preferably, the respective first and/or second arm sections of thearticulated arms are/is formed as a carbon rod. As a result, the armsections are particularly sturdy while at the same time beingcomparatively light in weight.

Finally, another advantageous embodiment of the invention ischaracterized in that the ends of the first and/or second arm sectionsof the articulated arms are at least partially made of plastic materialwith good slip properties, in particular of base polymers, fibers andfillers as well as solid lubricants, preferably of Iglidur®. This allowsfor frictionless movement of the articulated arms. The Iglidur® materialreduces wear at the ends of the arm sections during operation.

Other features and advantages of the invention will be apparent from thefollowing detailed description of exemplary embodiments of theinvention, taken in conjunction with the figures of the drawing, whichshows details of the invention. The individual features may beimplemented alone or in any combination in variants of the invention.

FIG. 1 shows a stretch film packaging machine 10 having a labelingdevice 11 for applying a label to an article 12. Labeling device 11 isdisposed at two printers 13 a, 13 b for printing the labels. A deltarobot 14 of labeling device 11 serves to convey the label from adispensing device 15 of printer 13 a to article 12. The robot has threearticulated arms 16 a, 16 b, 16 c. Articulated arms 16 a-16 c are eachconnected at a first end 18 a to a robot base 19 and at a second end 18b to a pickup device 21, which, in a pickup position shown in FIG. 1 ,takes the label from dispensing device 15 of printer 13 a. A weighingdevice 23 of stretch film packaging machine 10 is used for weighingarticle 12.

FIG. 2 shows a side view of labeling device 11, including robot base 19,pickup device 21, and the articulated arms 16 a-16 c connecting them.Articulated arms 16 a-16 c are attached to a platform 20 of pickupdevice 21. The articulated arms have first and second arm sections 17 a,17 b which are articulated to one another. The second arm section hastwo rods 53 a, 53 b arranged in parallel. Articulated arms 16 a-16 c areeach pivotable about a respective axis of rotation at robot base 19 anddriven by a respective motor 22 a, 22 b, 22 c fixedly mounted to robotbase 19. Pickup device 21 has a plunger 24 for picking up the label,which protrudes downwardly from a protective housing 25 of pickup device21 in the direction of gravity. A suction head 46 for sucking labelsagainst it is mounted to plunger 24. Robot base 19 is connected toplatform 20 by a return element 26 for mechanically returning pickupdevice 21 against gravity to its home position in the idle state ofrobot 14. The robot base includes a control unit 35 for controllingrobot 14.

FIG. 3 a shows a first side view of pickup device 21 without protectivehousing 25 (see FIG. 2 ). Plunger 24 includes a fixed portion 28 that ismounted to a base plate 27 and is not displaceable relative to baseplate 27 in longitudinal direction LA of plunger 24, and furtherincludes a portion 29 that is movable in fixed portion 28 inlongitudinal direction LA of plunger 24 and has a front end 30 a towhich the suction head 24 for picking up the label is mounted. Plunger24 protrudes through base plate 27 of pickup device 21. In the unloadedcondition, a spring element 31 retains movable portion 29 of plunger 24in an extended position 32, in which front end 30 a of plunger 24 isfurther away from base plate 27 than in a retracted position 33 (seeFIG. 3 c ) to enable picking up of the label. Bundled connections 51 aserve to connect sensors (of pickup device 21 to control unit 35 (seeFIG. 2 ). Movable portion 29 of plunger 24 is displaceable in thedirection of longitudinal axis LA of plunger 24 through fixed portion 28of plunger 24 toward base plate 27 to a retracted position 33. A rotarymotor 38 on base plate 27 is used to rotate movable portion 29 ofplunger 24 about its longitudinal axis LA.

FIG. 3 b shows a second, more detailed side view of pickup device 21with plunger 24 in extended position 32. In particular, there isillustrated an air hose 39 which provides a connection between a vacuumpump 40 disposed on base plate 27 and plunger 24. Air is withdrawn fromplunger 24 through air hose 39 to produce a negative pressure in plunger24 in order to suck the label against it. A Hall-effect sensor 36 islocated on fixed portion 28 of plunger 24 to measure a change in amagnetic field of a permanent magnet 37 on movable portion 29 of plunger24 (see FIG. 4 c ) and to thereby measure a movement of movable portion29 of plunger 24. Hall-effect sensor 36 is connected to control unit 35(see FIG. 2 ) to indicate displacement of movable portion 29 of plunger24. Air hose 39 is connected to the plunger via a coupling 60. A nut 61is used to retain coupling 60 in its position.

FIG. 3 c shows a side view of pickup device 21 with plunger 24 inretracted position 33. In retracted position 33, spring element 31 isloaded. Permanent magnet 37 is spaced apart from Hall-effect sensor 36in the axial direction along longitudinal axis LA of plunger 24.

FIG. 4 a shows a side view of plunger 24 where portion 29 of plunger 24,which is movable in fixed portion 28 of plunger 24, is in retractedposition 33.

FIG. 4 b shows a corresponding isometric view of plunger 24 in retractedposition 33. Movable portion 29 and fixed portion 28 of plunger 24 areformed cylindrically as a tube. Plunger 24 has a mechanical pressureregulator 41 for breaking a negative pressure in plunger 24, whichnegative pressure is used to pick up the label. Mechanical pressureregulator 41 includes in particular an opening 42 in movable portion 29of plunger 24. Opening 42 is formed closer to a rear end 30 b of movableportion 29 of plunger 24 opposite its front end 30 a than it is to itsfront end 30 a. When movable portion 29 of plunger 24 is in retractedposition 33 as shown, opening 42 is not covered by fixed portion 28 ofplunger 24.

FIG. 4 c shows a cross section through plunger 24 with opening 42 inmovable portion 29, which is axially movably supported in fixed portion28 of plunger 24. Movable portion 29 is in retracted position 33.Movable portion 29 of plunger 24 has a cavity 43 extending alonglongitudinal axis LA of plunger 24 from rear end 30 b of movable portion29 of plunger 24 to front end 30 a of plunger 24. Opening 24 extendsfrom outer surface 44 of movable portion 29 to cavity 43. When, in theextended position 32 of movable portion 29 of plunger 24, opening 24 iscovered by fixed portion 28 of plunger 24, a negative pressure can beproduced in cavity 43 by withdrawing the air therefrom in order to sucka label onto front end 30 a of plunger 24. Cavity 43 has a rearreceptacle 45 a at rear end 30 b for air hose 39 (see FIG. 3 b ) and afront receptacle 45 b at front end 30 a for the suction head 46 (seeFIG. 2 ) used to suck the label against it. Mounted to the rear end 30 bof movable portion 29 of plunger 24 is a permanent magnet 37, whosemagnetic field is measured by a Hall-effect sensor 36 (see FIG. 3 a ).Permanent magnet 37 is ring-shaped, so that it is aligned withHall-effect sensor 36 in any angular position.

FIG. 4 d shows a side view of plunger 24 in extended position 32. Whenmovable portion 29 of plunger 24 is in extended position 32, opening 42(see FIG. 4 a ) in movable portion 29 of plunger 24 is covered in agas-tight manner by fixed portion 28 of plunger 24 to enable picking upof the label. This allows a negative pressure to be produced in plunger24.

FIG. 5 a shows an isometric view of an elastic tension cord 48 of returnelement 26 (see FIG. 2 ) or of the retraction device, the tension cordbeing made in particular of rubber or latex. Tension cord 48 or thetension belt is provided at both ends with spherical cord holders 49 a,49 b by which tension cord 48 is attached to pickup device 21 and torobot base 19 (see FIG. 2 ).

FIG. 5 b shows an isometric view of return element 26 with tension cord48 and with a power cable 50 wound around tension cord 48, in particularin a helical path. Power cable 50 supplies data and power to pickupdevice 21 (see FIG. 1 ) via connections 51 c, 51 d.

FIG. 5 c shows an isometric view of return element 26 with tension cord48 and power cable 50. Tension cord 48 is attached to platform 20 ofpickup device 21 (see FIG. 2 ) and to a fastening element 52 of robotbase 19 (see FIG. 2 ).

FIG. 6 a shows an exploded view of one of articulated arms 16 a-16 c oflabeling device 11 (see FIG. 2 ), here, by way of example, articulatedarm 16 a with first and second arm sections 17 a, 17 b. Rod 53 a isshown here by way of example for the two parallelly guided rods 53 a, 53b of second arm section 17 b. Second arm section 17 b of articulated arm16 a has a first and/or a second end 54 a, 54 b, each having a lug 55.Lug 55 has a circular through-receptacle 56 with an outwardly directedslot 57 for holding a spherical screw head 58. Screw 59 with screw head58 is threaded into first arm section 17 a in order to pivotablyarticulate first and second arm sections 17 a, 17 b together.

Finally, FIG. 6 b shows the articulated arm 16 a connected to a robotbase 19 and to pickup device 21. Spherical screw heads 58 are insertedin lugs 55 at the ends 54 a, 54 b of second arm section 17 b. Screws 59(see FIG. 6 a ) with screw heads 58 are threaded in platform 20 ofpickup device 21 and in first arm section 17 a to connect pickup device21 to second arm section 17 b. Lugs 55 embrace the spherical screw heads58 frictionally, and possibly also with a form fit. The through-holes oflugs 55 are formed by an inner radius of the lug, which has a reciprocalspherical geometry.

When inserting a spherical screw head, the lug is forced apart,whereupon it clamps the screw head therein so that it cannot slide outsideways from the lug.

While subject matter of the present disclosure has been illustrated anddescribed in detail in the drawings and foregoing description, suchillustration and description are to be considered illustrative orexemplary and not restrictive. Any statement made herein characterizingthe invention is also to be considered illustrative or exemplary and notrestrictive as the invention is defined by the claims. It will beunderstood that changes and modifications may be made, by those ofordinary skill in the art, within the scope of the following claims,which may include any combination of features from different embodimentsdescribed above.

The terms used in the claims should be construed to have the broadestreasonable interpretation consistent with the foregoing description. Forexample, the use of the article “a” or “the” in introducing an elementshould not be interpreted as being exclusive of a plurality of elements.Likewise, the recitation of “or” should be interpreted as beinginclusive, such that the recitation of “A or B” is not exclusive of “Aand B,” unless it is clear from the context or the foregoing descriptionthat only one of A and B is intended. Further, the recitation of “atleast one of A, B and C” should be interpreted as one or more of a groupof elements consisting of A, B and C, and should not be interpreted asrequiring at least one of each of the listed elements A, B and C,regardless of whether A, B and C are related as categories or otherwise.Moreover, the recitation of “A, B and/or C” or “at least one of A, B orC” should be interpreted as including any singular entity from thelisted elements, e.g., A, any subset from the listed elements, e.g., Aand B, or the entire list of elements A, B and C.

LIST OF REFERENCE CHARACTERS

-   -   10 stretch film packaging machine    -   11 labeling device    -   12 article    -   13 a,b printer    -   14 robot    -   15 dispensing device    -   16 a-c articulated arms    -   17 a,b arm sections    -   18 a,b ends of the articulated arms    -   19 robot base    -   20 platform    -   21 pickup device    -   22 a-c motor    -   23 weighing device    -   24 plunger    -   25 protective housing    -   26 return element    -   27 base plate    -   28 fixed portion of the plunger    -   29 movable portion of the plunger    -   30 a,b ends of the movable portion of the plunger    -   31 spring element    -   32 extended position of the plunger    -   33 retracted position of the plunger    -   34 power cable    -   35 control unit    -   36 Hall-effect sensor    -   37 permanent magnet    -   38 rotary motor    -   39 air hose    -   40 vacuum pump    -   41 mechanical pressure regulator    -   42 opening    -   43 cavity    -   44 outer surface    -   45 a,b receptacles    -   46 suction head    -   48 elastic tension cord    -   49 a,b spherical cord holders    -   50 power cable    -   51 a,b connections    -   52 fastening element    -   53 a,b parallelly guided rods    -   54 a,b ends of the second section of the articulated arm    -   55 lug    -   56 circular through-receptacle    -   57 slot    -   58 screw head    -   59 screw    -   60 air hose coupling    -   61 nut    -   LA longitudinal axis/longitudinal direction of the plunger

1. A labeling device for a stretch film packaging machine, the labelingdevice comprising: a pickup device moveable to pick up a label, thepickup device including a platform, a base plate and a plungerconfigured to pick up the label; and a delta robot comprising at leasttwo articulated arms and a robot base, each of the articulated armscomprising a first arm section and a second arm section, which arearticulated to one another, the articulated arms each being articulatedat a first end to the robot base and at a second end to the platform,and the articulated arms each being pivotable about a respective axis ofrotation at the robot base and configured to be driven by a respectivemotor fixedly mounted to the robot base, wherein the plunger is mountedso as to be rotatable relative to the base plate about the longitudinalaxis of the plunger by a rotary motor mounted on the base plate.
 2. Thelabeling device as recited in claim 1, wherein the plunger comprises afixed portion mounted to the base plate so as to be not displaceablerelative to the base plate in a longitudinal direction of the plunger,and a moveable portion that is movable in the longitudinal direction ofthe plunger, the moveable portion having a front end configured to pickup the label.
 3. The labeling device as recited in claim 2, wherein thefixed portion of the plunger is rotatably disposed in a rotary bearingin the base plate.
 4. The labeling device as recited in claim 2, whereinthe pickup device comprises a gear mechanism mounted to the base platefor rotating the plunger by a rotation of the motor.
 5. The labelingdevice as recited in claim 2, wherein the fixed portion of the plungeris immovably secured to the base plate, and the movable portion isrotatably supported relative to the fixed portion.
 6. The labelingdevice as recited in claim 1, wherein the pickup device includes asuction head mounted to the front end of the movable portion andconnected via the movable portion of the plunger to a vacuum pumpmounted on the base plate.
 7. The labeling device as recited in claim 6,further comprising an air hose connecting the vacuum pump to the movableportion of the plunger by a coupling.
 8. The labeling device as recitedin claim 1, wherein the movable portion of the plunger is displaceablein a longitudinal direction of the plunger between an extended positionfor picking up the label and a retracted position, wherein the air hoseis movable only with the movable portion of the plunger between theretracted position and the extended position but immovable in an axialdirection relative to the plunger.
 9. The labeling device as recited inclaim 2, wherein the movable portion or the fixed portion of the plungeris tubular.
 10. The labeling device as recited in claim 2, wherein inthe unloaded condition, the movable portion of the plunger is retainedin the extended position by a spring.
 11. The labeling device as recitedin claim 2, wherein a permanent magnet is mounted to the rear end of themovable portion of the plunger opposite the front end of the movableportion of the plunger, wherein the pickup device comprises aHall-effect sensor for measuring the magnetic field of the permanentmagnet, and wherein the Hall-effect sensor is connected to a controllerconfigured to indicate displacement of the movable portion of theplunger.
 12. The labeling device as recited in claim 11, wherein theHall-effect sensor and the permanent magnet are located at a same heightrelative to the base plate when the movable portion of the plunger is inthe extended position.
 13. The labeling device as recited in claim 1,further comprising a return element connecting the robot base to theplatform and configured to mechanically return the pickup device againstgravity to a home position in an idle state of the robot.
 14. Thelabeling device as recited in claim 13, wherein the return elementincludes an elastic tension cord.
 15. The labeling device as recited inclaim 14, further comprising a power cable for supplying power to thepickup device disposed on and carried by the tension cord.
 16. Thelabeling device as recited in claim 1, wherein each of the second armsections of the articulated arms has a first end or a second end with alug having a circular, outwardly slotted through-receptacle configuredto hold a spherical screw head.
 17. The labeling device as recited inclaim 16, wherein spherical screw head is inserted in the lug forconnecting the first arm section and the second arm section to oneanother or to the platform or to the robot base, the respective lugfrictionally embracing the spherical screw head.
 18. The labeling deviceas recited in claim 1, wherein the respective first arm section or therespective second arm section of the articulated arms is formed as acarbon rod.
 19. The labeling device according to claim 16, wherein theends of the first arm section or the second arm section of thearticulated arms are at least partially made of plastic material havingslip properties.
 20. The labeling device according to claim 2, wherein amechanical pressure regulator comprises the opening in the movableportion of the plunger.
 21. The labeling device according to claim 20,wherein the movable portion of the plunger is configured to be displacedin longitudinal direction due to contact with a stretch film packagingsuch that the plunger is placed in a retraction position, uncovering theopening and breaking a negative pressure such that the label is releasedfrom the plunger.